NOT APPLICABLE
This invention has been created without the sponsorship or funding of any federally sponsored research or development program.
This invention relates to an internal combustion engine of the piston cylinder type with one or more cylinders having rotary valves for the introduction of the fuel/air mixture into the cylinder and the evacuation of exhaust gases.
Typical internal combustion engines employ poppet type valves which require valve trains comprised of camshaft, flower, valve spring, etc. These conventional components have many well-known mechanical and thermal inefficiencies associated with them ultimately reducing engine efficiency.
A typical internal combustion engine""s camshaft is designed with fixed valve opening and closing positions as well as duration of valve opening with respect to the crankshaft, thus fixing valve timing as well as valve flow characteristics. It is well known by the prior art that fixed valve timing does not take advantage of changing charge momentums which vary with engine load. Not using a full range of charge momentums greatly reduces the pumping efficiency of the engine. Therefore, the design of the present internal combustion engines is a compromise to best suit only a single optimal operating range with a certain charge momentum. Consequently, the engines efficiency decreases as the engine speed increases or decreases from that of the optimal operating range.
There are many designs of internal combustion engines utilizing rotating valves for the exchange of intake and exhaust gases which have proven superior to traditional poppet valve designs. However. many of these rotary valve designs have their own problems associated with them such as binding, sealing, and longevity issues. However, inventions have been designed to work in conjunction with cylindrical rotary valves which effectively adjust the timing and duration of the valve opening.
These issues have been solved with the use of a spherical rotary valve U.S. Pat. No. 5,361,739, shows one spherical intake drum and one spherical exhaust drum per cylinder. The cylinder head is split consisting of an upper and lower half both having a hemispherical shaped cavity which when assembled forms a complete spherical shaped cavity which houses the spherical drum valves. Both the intake and exhaust valve have a passageway which communicates with inlet or outlet ports in the cylinder head to introduce the air-fuel mixture or evacuate the exhaust, respectively. Gas tight sealing for both the intake and exhaust valves is accomplished with U.S. Pat. No. 4,976,232 disclosing an O-ring type seal which is positioned in the lower portion of the split head around the intake and exhaust ports, respectively. However, this design also has fixed valve timing.
Rotary valves have been developed to adjust the timing and duration of the valves of an engine. For example, U.S. Pat. No. 3,993,036, shows a rotary valve having a spring loaded sleeve at the trailing edge of the rotary valve. The sleeve does not allow for adjustment of the opening of the valve. Further, the sleeve may only retard the closing of the valve at high revolutions per minute (RPM) of the engine. In addition, the timing and duration cannot be controlled on command by engine load.
U.S. Pat. No. 4,163,438 shows rotary valves that may be axially displaced in a cylinder head to change the timing of the valves. However, the airflow through the valves is changed. Further, as RPM of the engine increases, it may be desirable to provide greater airflow into the combustion chamber. Furthermore, the complexity of the system may add to manufacturing costs.
U.S. Pat. No. 4,421,077 shows flappers positioned near the leading and trailing edges of an intake rotary valve. The flappers may increase the length of the port of the intake rotary valve allowing the timing of the valve to change. However, the opening of the flappers depends upon the pressure across the opening of the intake valve and the flappers will usually only open at high RPM""s. Further, the timing of valves may not be controlled upon command during engine operation.
U.S. Pat. No. 5,205,251 discloses a rotary valve disposed within a rotatable sleeve. The sleeve has openings on opposing sides in order to change the timing of the valve. However, when changing the timing of the valves, only the closing of the intake valve and the opening of the exhaust valve will usually be changed.
U.S. Pat. No. 5,392,743 discloses a single rotary valve positioned on a shaft that is axially displaced by a cam to varying an open duration of the valve. Further, the complexity of the valve assembly may increase manufacturing and repair costs.
These and other difficulties experienced with the prior art rotary valve systems for internal combustion engines have been obviated by the present invention.
It is, therefore, a principal object of the present invention to provide a rotary valve system for an internal combustion engine that is adjustable for controlling the cross-sectional flow area and valve opening duration of the air intake and exhaust ports.
Another object of the invention is the provision of a rotary valve system for an internal combustion engine that is adjustable for selectively reducing the valve opening duration of the air intake and exhaust ports and for selectively making a reduction of the opening early or late in the open phase.
A further object of the invention is the provision of a spherical rotary valve assembly for use with an internal combustion engine of the piston cylinder type which can dynamically adjust the opening and closing of the intake and exhaust valves independently to meet real time changing engine loads.
It is another object of the invention to provide a rotary valve assembly for an internal combustion engine which has a quieter, more reliable operation efficiency peak in comparison to a traditional poppet valve design.
A still further object of the invention is the provision of a rotary valve assembly for an internal combustion engine which can be dynamically adjusted for the timing of the valve opening and which has fewer moving parts than previous rotary valve designs.
It is a further object of the invention to provide a rotary valve assembly for an internal combustion engine that provides higher engine performance and efficiency than previous poppet valve and rotary valve designs.
The present invention generally comprises a spherical rotary valve having a port forming a leading edge and a trailing edge perpendicular to the axis of valve rotation which communicates with a similar port of the cylinder head. The valves are spherical and housed in a spherical shaped cavity of a split cylinder head consisting of an upper and lower half both having hemispherical shaped cavities.
The lower portion of the cylinder head comprises a single combustion chamber per cylinder. A spherical rotary valve opens or closes a passage from an induction system capable of creating the air/fuel supply which is in communication with the combustion chamber. A spherical rotary valve opens or closes a passage from an exhaust system which is in communication with the combustion chamber. The induction system is attached to the upper portion of the cylinder head such that it is free flowing into the intake port. The exhaust system is attached to the upper portion of the cylinder head such that it is free flowing out of the exhaust port.
A valve seal is housed in the lower portion of the cylinder head which surrounds the intake passageway in to the combustion chamber. A valve seal is housed in the lower portion of the cylinder head which surrounds the exhaust passageway in to the combustion chamber. The seal protrudes past the hemispherical cavity housing in order to contact a tangent line around the valve. The seal is pressed against the surface of the valve by the compression and combustion pressures with the combustion chamber. The pressure within the combustion chamber actuates the seals through passageways or pressure bleeders.
The device includes two gates, one to affect the leading edge and one to affect the trailing edge of the valve port. The movement of the gate affects cross-sectional area of the port. The gates are positioned with a sufficiently small distance between the spherical rotary valve in the upper portion of the cylinder head such that their linear motion is in the direction perpendicular to the ports path of flow. The linear motion of the gates is generally accomplished with solenoids, servos, vacuum motors, or any device capable of providing four ounces of push or pull. The actuation of the gates is generally controlled by a processor sensing engine speed, throttle position,. induction system pressure, exhaust system pressure, combustion chamber pressures, and any other such engine load variable.
According to another aspect to the invention, the distance of the gate above the valve must be sufficiently small while not contacting the spherical valve. The space now formed between the valve and gate is considered unsealed dead space. The dead space effectively chokes the flow in communication with the ports in the upper cylinder head and the ports of the spherical valve providing an effective closed valve.